Unique Lipid Walls

Bacteria keep poisons behind unique lipid walls, according to reports in Nature vol. 419, p708, 17 Oct 2002 and ScienceNOW 18 oct 2002. Anammox bacteria make energy by converting ammonium and nitrates to nitrogen gas. The intermediate steps in this process produce poisons that could kill the bacteria by attacking their proteins and DNA. To keep such poisons out of harm's way the bacteria keep them enclosed in a membrane that has a unique structure not seen in other living cells. Normal membranes are double layers of lipid molecules shaped like a string with a knob on the end. The knobs form the outer surfaces of the layer with the strings pointing into the middle of the layer. This structure is flexible and allows other molecules pointing in to push through. But such membranes in the Anammox bacteria would allow the poisonous chemicals to leak. Instead, membranes in Anammox bacteria are made of lipids called ladderanes that have zig-zag strings that pack tightly together so poisons cannot escape. "It's the most dramatically different lipid discovered in a long time," commented Gary Olsen, a microbiologist at University of Illinios, Urbana-Champaign. "It's a neat trick because it's not an obvious extension from other known lipids. The steps it took to evolve are not at all clear."

Editorial Comment: The steps taken to evolve ladderanes from ordinary membrane lipids are "not clear" because they could not have existed. Ladderane membranes had to be fully formed and functional if they were going to successfully keep poisonous chemicals under control. It makes far more sense to admit ladderanes were made by an intelligent Creator who saw the problem and built in the solution when He made the bacteria. (Ref. ladderanes, lipids, bacteria)